Enameling metal.



No. 774,491 PATENTED NOV. 8, 1904.

G. P. PFALZGRAF.

ENAMELING METAL.

APPLICATION FILED DEG. 16, 1903.

Patented November 8, 1904.

UNTTED STATES PATENT TTTcn.

CHARLES F. PFALZGRAF, OF BALTIMORE, MARYLAND.

ENAMELING METAL.

SPECIFICATION forming part of Letters Patent No. 774,491, dated November8, 1904:.

Application filed December 16, 1903. Serial No. 185,336. N0 model-l To(all whom, it may concern:

Be it known that I, CHARLES F. PFALZGRAF, a citizen of the UnitedStates, residing at Baltimore. in the State of Maryland, have inventedcertain new and useful Improvements in Enameling Metal, of which thefollowing is a specification.

This invention relates to a new and useful article of enameled sheetmetal and to a method of producing the article.

One object of this invention is to prepare the surface of sheet metaleither in the form of sheets or in the form of ware, vessels, or otherarticles of utility to receive a coating of enamel, which is then to besubjected to heat. In this preparation of the metal practically theentire surface is provided with minute cavities or crevices havingundercuts.

Another object of this invention is to provide sheet metal either in theform of sheets or in the form of ware, vessels, or other articles ofutility with a coating of enamel, the enamel covering the metal surface,which has previously been provided with minute cavities and crevices,which will have undercuts, all of said cavities and crevices beingarranged to produce a predetermined design, such as figures, outlines,or ornamentations, which may be seen through the enamel coat.

In carrying out the inventive idea here involved the sheet metal may besubjected to the necessary operations to produce the cavities orcrevices with undercuts either before the stamping operation for givingform to the article or after the article has been shaped. I prefer toemploy mechanical means to produce the cavities or crevices withundercuts and to do this while the metal is in the sheet that is, priorto being shaped or stampedas the metal sheets may while either hot orcold be run through suitable rolls in order that the upraised particlesof metal along the lines of the incision will be upset or compressedsufliciently to cause said particles to partly overlap the grooves ofthe said incised lines, and thereby produce undercuts or cavities. Forsome purposes it may be desirable to do the work of providing theundercuts or cavities after the sheets have been pickled and cleanedpreparatory to enameling. There is no limit to any specific depth orangle of cut for the lines of etching or incising to produce the desiredundercuts or cavities; but I prefer to have these cuts as deep as willenamel smoothly by the application of one coat. I

The enamel employed may be smelted, ground, applied to and burned on themetal articles by any of the methods now employed. Any of the enamelcompounds now or formerly made can be utilized and a much improvedarticle produced by fusing to the metal base after the latter has beenprepared as herein described. I may use either opaque or transparentenamels; but by omitting from the enamel formula opacity-producingingredients I get a comparatively transparent or stained enamel, throughwhich when burned the design will be visible and appear ornamental anddecorative.

By etching or incising mechanically-that is, by the use of gravers,rolls, &c.it is possible to produce cheaply exact duplicates of anypredetermined designs.

Referring to the drawings, Figure l illustrates a piece of a plate ofsheet metal having on its surface etchings and incisions and forming apredetermined design. Fig. 2 shows an enlarged sectional view through anincision in a plate. Fig. 3 shows a similar view after the metal at theedge of the incision has been compressed to form the undercut. Fig. 4shows a vessel with an etched design and enameled. p The rough lineincision and subsequent compression of the upraised or rough edges alongthe lines of incision form cavities or undercuts which bind the enamelcoating after it is fused to the metal base with a tenacity yetunequaled.

If the metal sheets are to be used for stamping, the operation ofcompressing or upsetting after making the line-incisions may sometimesbe omitted, as in some articles the stamping operation has a tendency tocompress or upset and divert the rough metal along the incised linessufiiciently to produce minute cavities and undercuts.

Having thus fully described my invention,

what I claim as new, and desire to secure'by Letters Patent, is

1. An enameled article havinga metal base provided with incisionsextending partly through said metal and having the edges of the metal atsaid incisions projecting partly over the incisions, and a vitreousenamel coating the entire surface of said article and filling saidincisions.

2. An article of enameled metal Ware whose metal surface has incisionsand cavities pro vided with undercuts and forming ornamental designs,and a coating of enamel covering the entire surface and filling theincisions and cavities and through which enamel the said design may beseen, as set forth.

3. The method of preparing sheet metal for a coating of enamelconsisting of first preparing the surface of the sheet metal by formingthereon incisions having upraised particles of metal along the lines ofthe incisions; and then upsetting or compressing the said upraisedparticles sufiicient to cause them to overlap the minute grooves of theincisions and create 3 undercuts.

L. The method of applyingvitreous enamel 1 to thin sheet metal,consisting of first preparing the surface of the sheet metal by formingthereon incisions and cavities which have undercuts; then coating theentire surface with liquid vitreous enamel so as to fill the saidincisions and cavities, and finally subjecting the sheet metal to heatin a muffle to convert the enamel into a glazed surface.

5. The method of enameling sheet metal, consisting of first preparingthe surface of the sheet metal by forming thereon incisions havingupraised particles of metal along the lines of the incisions; thenupsetting or compressing the said upraised particles suflicient to causethem to overlap the minute grooves of the incisions and createundercuts; then coating the entire surface of the metal with enamel andfilling the incisions and undercuts with enamel, and then fusing theenamel.

In testimony whereof I affix my signature in the presence of twowitnesses.

CHARLES F. PFALZGRAF.

Witnesses:

OHAn ns B. MANN, J r., W M. D. PoULTNnY.

